Which condition is the primary cause of Conn syndrome in adults?

Conn syndrome, also known as primary hyperaldosteronism, is primarily caused by an adrenal adenoma in adults. This condition results in excess production of aldosterone, which leads to sodium retention, potassium excretion, and increased blood volume, ultimately causing hypertension. The presence of an adrenal adenoma, which is a benign tumor of the adrenal gland, is responsible for this overproduction of aldosterone.

The understanding of this condition helps differentiate it from other causes of increased aldosterone levels, such as those that may be associated with genetic factors, high angiotensin II levels, or elevated plasma renin. While these factors can influence aldosterone secretion, the most common underlying pathological entity in adults with Conn syndrome is indeed an adrenal adenoma. This distinction is crucial for diagnosis and subsequent treatment options.